Vehicle Control Method and Vehicle Control Device

The present disclosure relates to a vehicle control method and a vehicle control device.

For example, it is known that charging efficiency of a secondary battery decreases in a low-temperature environment. Patent Literature 1 discloses that a vehicle includes an external flow path, a PTC heater, four internal flow paths and four temperature sensors corresponding to four batteries, external and internal control valves, and a control device that charges the four batteries while shifting charging start timings, the control device supplies hot water heated by the PTC heater to the internal flow path of the battery having a temperature lower than a first temperature, supplies hot water heated by heat exchange with the battery being charged to the internal flow path of the battery not yet being charged when there are the battery being charged that is at or above a second temperature and the battery not yet being charged that is below the first temperature, and supplies the hot water heated by the heat exchange with the battery being charged to the external flow path when there is no battery not yet being charged.

However, in Patent Literature 1, since temperatures of the four batteries are adjusted using only the hot water, variations in temperature tend to occur among the batteries, making it difficult to heat the batteries substantially uniformly.

An object of the present disclosure is to provide a technique for substantially uniformly heating a chargeable and dischargeable battery mounted on a vehicle.

A vehicle control method executable in a vehicle is provided.

The vehicle includes

The vehicle control method includes

A vehicle control device set to be mounted in a vehicle is provided.

The vehicle includes

In a case that a first temperature of the first battery pack and the second battery pack is lower than a first threshold temperature, the refrigerant is circulated through the first refrigerant layer of the first heat exchange plate at a first flow rate, and is circulated through the second refrigerant layer of the second heat exchange plate at a second flow rate lower than the first flow rate, and a second temperature of the refrigerant entering the first refrigerant layer is higher than the first temperature of the first battery pack, and then

These comprehensive or specific aspects may be implemented by a system, a device, a method, an integrated circuit, a computer program, or a recording medium, or any combination of the system, the device, the method, the integrated circuit, the computer program, and the recording medium.

According to the present disclosure, a chargeable and dischargeable battery mounted on a vehicle can be heated substantially uniformly.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, unnecessarily detailed description may be omitted. For example, detailed description of already well-known matters and redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate understanding of those skilled in the art. The accompanying drawings and the following description are provided for those skilled in the art to sufficiently understand the present disclosure, and are not intended to limit the subject matter described in claims.

is a plan view showing a configuration example of a vehicleaccording to a first embodiment.is a left side view showing the configuration example of the vehicleaccording to the first embodiment.

For convenience of description, as shown in, an axis extending in a height direction of the vehicleis taken as a Z axis. An axis perpendicular to the Z axis (that is, parallel to ground) and extending in a traveling direction of the vehicleis taken as a Y axis. An axis perpendicular to the Y axis and the Z axis (that is, an axis in a width direction of the vehicle) is taken as an X axis. For convenience of description, a positive direction of the Z axis may be referred to as “upper”, a negative direction of the Z axis may be referred to as “lower”, a positive direction of the Y axis may be referred to as “front”, a negative direction of the Y axis may be referred to as “rear”, a positive direction of the X axis may be referred to as “right”, and a negative direction of the X axis may be referred to as “left”. These expressions are the same for other drawings describing the XYZ axes. The expressions related to these directions are used for convenience of explanation, and are not intended to limit a posture of the structure in actual use.

As shown in, the vehicleincludes a vehicle body, wheels, an electric motor, a control device, a first heat exchange plate, a second heat exchange plate, first battery packs, and second battery packs. The control devicemay be read as a vehicle control device.

The wheelsare coupled to the vehicle body. Althoughshow an automobile in which the vehicleincludes four wheels, the vehiclemay include at least one wheel. For example, the vehiclemay be a motorcycle (bike) including two wheelsor a vehicle including three or five or more wheels. Further, one of the plurality of wheelsprovided in the vehiclemay be referred to as a first wheel, and one of the plurality of wheels, which is different from the first wheel, may be referred to as a second wheel. The first wheelmay be a front wheel of the vehicle, and the second wheelmay be a rear wheel of the vehicle. The vehicleis movable in a predetermined direction (for example, a front-rear direction of the vehicle) by the first wheeland the second wheel

The electric motordrives at least one wheel(for example, the first wheel) using electric power supplied from a secondary battery. The vehicleincludes at least one electric motor. The vehiclemay have a configuration in which the electric motordrives the front wheel (that is, a front wheel drive configuration). Alternatively, the vehiclemay have a configuration in which the electric motordrives the rear wheel (that is, a rear wheel drive configuration) or a configuration in which the electric motordrives both the front wheel and the rear wheel (that is, a four wheel drive configuration). Alternatively, the vehiclemay include a plurality of electric motors, and each of the plurality of electric motorsmay individually drive the wheel. The electric motormay be installed in a motor room (engine room) located in front of the vehicle.

The control deviceperforms various controls of the vehicle. The control devicemay be read as a vehicle control device, an electronic control unit (ECU), a processor, a controller, or the like.

The first heat exchange plateand the first battery packs, and the second heat exchange plateand the second battery packsare accommodated in the vehicle body.

The first heat exchange plateand the second heat exchange platemay be disposed along a predetermined direction (for example, the front-rear direction of the vehicle). The first heat exchange plateand the second heat exchange platemay be disposed along a direction orthogonal to the predetermined direction (for example, the front-rear direction of the vehicle), and the orthogonal direction may be a horizontal direction (for example, the width direction of the vehicle).

Each of the first battery packand the second battery packincludes one or more rechargeable secondary batteries. An example of the secondary battery is a lithium ion battery. The secondary battery supplies (discharges) stored electric power to the electric motoror the like. The secondary battery may store (charge) electric power generated by the electric motorby regenerative energy. As shown in, the first heat exchange plateand the first battery packs, and the second heat exchange plateand the second battery packsmay be accommodated under a floor at a center of the vehicle body. Details of the configurations of the first heat exchange plateand the second heat exchange platewill be described later.

is a diagram showing an example of an electric circuit provided in the vehicleaccording to the first embodiment.

The first battery packand the second battery packeach including a secondary battery have a high-voltage connector and a low-voltage connector. In the present disclosure, the high-voltage connector and the low-voltage connector are referred to as electrical connectors without being distinguished from each other.

A high-voltage distributor may be connected to the high-voltage connector. The high-voltage distributor may be connected to a drive inverter, an electric compressor, a heating, ventilation, and air conditioning (HVAC), an in-vehicle charger, and a quick-charging port. The low-voltage connector may be connected to a controller area network (CAN) and a 12 V power supply system.

The electric motormay be connected to the drive inverter. That is, the electric power output from the secondary battery may be supplied to the electric motorthrough the high-voltage connector, the high-voltage distributor, and the drive inverter.

is a plan view showing an arrangement example of the first heat exchange plateand the first battery packsaccording to the first embodiment.is a plan view showing an arrangement example of the second heat exchange plateand the second battery packsaccording to the first embodiment.is a cross-sectional view showing an arrangement example of the first heat exchange plateand the first battery packsaccording to the first embodiment.is a cross-sectional view showing an arrangement example of the second heat exchange plateand the second battery packsaccording to the first embodiment.shows a cross-sectional view taken along a line A-A in, andshows a cross-sectional view taken along a line B-B in.

The first heat exchange plateand the second heat exchange platemay have a flat, substantially rectangular parallelepiped shape. The first heat exchange plateand the second heat exchange platemay be read as heat exchangers.

The first battery packsare disposed along a first surface. The first heat exchange plateis disposed along the first surface. The first surface may be a floor surface of the vehicle body. The second battery packsare disposed along a second surface. The second heat exchange plateis disposed along the second surface. The second surface may be a floor surface of the vehicle body.

As shown in, the first heat exchange plateincludes a third surfacedisposed along the first surface and capable of exchanging heat with the first battery packs, and a fourth surfacedisposed along the first surface and opposite to the third surface. Members of the third surfaceand the fourth surfacemay be made of metal, for example, aluminum. However, the third surfaceand the fourth surfaceare not limited to metal and may be made of other materials.

As shown in, the first heat exchange plateincludes a first refrigerant layerin which a refrigerant circulates between the third surfaceand the fourth surface, and a first coolant layerin which a coolant circulates between the third surfaceand the fourth surface. Examples of the refrigerant include hydrofluorocarbon (HFC). Examples of the coolant include an antifreezing solution containing ethylene glycol.

As shown in, in the present embodiment, the first coolant layeris disposed on the first refrigerant layer, and the first battery packsare disposed on the first coolant layer. However, the first refrigerant layermay be disposed on the first coolant layer, and the first battery packsmay be disposed on the first refrigerant layer.

As shown in, the first heat exchange plateincludes a first refrigerant input portionthat allows the refrigerant to enter the first refrigerant layer, and a first refrigerant output portionthat allows the refrigerant to exit from the first refrigerant layer.

As shown in, the first heat exchange plateincludes a first coolant input portionthrough which the coolant enters the first coolant layer, and a first coolant output portionthrough which the coolant exits from the first coolant layer.

As shown in, the second heat exchange plateincludes a fifth surfacedisposed along the second surface and capable of exchanging heat with the second battery packs, and a sixth surfacedisposed along the second surface and opposite to the fifth surface. Members of the fifth surfaceand the sixth surfacemay be made of metal, for example, aluminum. However, the fifth surfaceand the sixth surfaceare not limited to metal and may be made of other materials.

As shown in, the second heat exchange plateincludes a second refrigerant layerin which the refrigerant circulates between the fifth surfaceand the sixth surface, and a second coolant layerin which the coolant circulates between the fifth surfaceand the sixth surface.

As shown in, in the present embodiment, the second coolant layeris disposed on the second refrigerant layer, and the second battery packsare disposed on the second coolant layer. However, the second refrigerant layermay be disposed on the second coolant layer, and the second battery packsmay be disposed on the second refrigerant layer.

As shown in, the second heat exchange plateincludes a second refrigerant input portionthat allows the refrigerant to enter the second refrigerant layer, and a second refrigerant output portionthat allows the refrigerant to exit from the second refrigerant layer.

As shown in, the second heat exchange plateincludes a second coolant input portionthat allows the coolant to enter the second coolant layer, and a second coolant output portionthat allows the coolant to exit from the second coolant layer.

is a plan view showing a configuration example of the first refrigerant layeraccording to the first embodiment. The second refrigerant layermay have the same configuration.

As shown in, the first refrigerant layerincludes a first refrigerant passageextending in a predetermined direction (for example, a Y direction), a second refrigerant passagedisposed along the first refrigerant passage (for example, parallel to the first refrigerant passage), and a plurality of branch refrigerant passagesconnecting the first refrigerant passageand the second refrigerant passage. The refrigerant that has entered the first refrigerant input portionmoves through the first refrigerant passage, moves to the second refrigerant passagevia the plurality of branch refrigerant passages, and exits from the first refrigerant output portion. In the present embodiment, the first refrigerant passage, the second refrigerant passage, and the branch refrigerant passagesmay be collectively referred to as refrigerant passages.

The first battery packsmay be disposed on the branch refrigerant passagesin a plan view. Accordingly, the refrigerant moving through the branch refrigerant passagesof the first refrigerant layercan efficiently exchange heat with the first battery packvia the coolant moving through the first coolant layer.

is a plan view showing a configuration example of the first coolant layeraccording to the first embodiment. The second coolant layermay have the same configuration.

As shown in, the first coolant layerincludes a first coolant passageextending in the predetermined direction (for example, the Y direction), a second coolant passagedisposed along the first coolant passage(for example, parallel to the first coolant passage), and a third coolant passageconnecting the first coolant passageand the second coolant passage. The coolant that has entered from the first coolant input portionmoves through the first coolant passage, the third coolant passage, and the second coolant passagein this order, and exits from the first coolant output portion. In the present embodiment, the first coolant passage, the third coolant passage, and the second coolant passagemay be collectively referred to as coolant passages.

Heat exchange is performed between the refrigerant moving through the refrigerant passages of the first refrigerant layerand the coolant moving through the coolant passages of the first coolant layer, and a temperature of the third surfaceis made substantially uniform. Accordingly, a temperature of the first battery packscapable of exchanging heat with the third surfacecan be adjusted substantially uniformly. Temperature adjustment includes both heating and cooling, and means that the temperature is adjusted to an appropriate temperature. Similarly, the heat exchange is performed between the refrigerant moving through the refrigerant passages of the second refrigerant layerand the coolant moving through the coolant passages of the second coolant layer, and a temperature of the fifth surfaceis made substantially uniform. Accordingly, a temperature of the second battery packswhich is capable of exchanging heat with the fifth surfacecan be adjusted substantially uniformly.

is a schematic diagram showing an example of a refrigerant circuit and a coolant circuit in a first heating mode according to the first embodiment.

The first heating mode is performed when the temperatures of the first battery packsand the second battery packsare equal to or lower than a first threshold temperature. The first threshold temperature corresponds to a lower limit of a temperature suitable for efficient charging of the secondary battery, and is, for example, 5° C. However, the first threshold temperature may be lower than 5° C. or higher than 5° C. The temperature of first battery packsmay be measured by a temperature sensor (not shown) attached to first battery packs. The temperature of the second battery packsmay be measured by a temperature sensor (not shown) attached to the second battery packs.

In the first heating mode, the refrigerant is circulated through the first refrigerant layerof the first heat exchange plateat a first flow rate. In the first heating mode, a temperature of the refrigerant entering the first refrigerant layeris higher than the temperature of the first battery packs. Specifically, as shown in, the control deviceforms the refrigerant circuit that allows the refrigerant to circulate through a compressorthat compresses the refrigerant, the first refrigerant input portion, the refrigerant passages of the first refrigerant layer, the first refrigerant output portion, and an expansion valvethat expands the refrigerant in this order as the first heating mode. For example, when the refrigerant at 80° C. enters the first refrigerant input portionand moves through the refrigerant passages of the first refrigerant layer, the refrigerant exchanges heat with the coolant of the first coolant layer, and for example, the refrigerant at 50° C. exits from the first refrigerant output portion. The control devicemay form the refrigerant circuit shown inby controlling a three-way valve, a four-way valve, or the like (not shown).

In the first heating mode, the refrigerant may be circulated through the second refrigerant layerof the second heat exchange plateat a second flow rate smaller than the first flow rate. However, the second flow rate may be zero. That is, in the first heating mode, there may be little or no refrigerant flowing through the second refrigerant layerof the second heat exchange plate.